[RussWhite]

As I recall mine pulled intake air from my basement airs and from the same area that air for those units is pulled. In my case, through filters located between steps on my mid-entry. My four hoses were all ouputs with two going to the heat exchanger under the credenza and the other two hoses going to the dash, one on each side for driver and passenger.
I guess I would make sure all is well with the two speed switch before going to the trouble of removing the plenum. Once the plenum is removed no matter what I found, even if it was just a broken wire or bad connection, I would replace the fan motor based on experience of other Newell owners. Russ